Building the Bridge: Devising An Architecutre to Migrate Voice Band Calls to Packet Transport and Multi-Media Services

One of the greatest challenges int he migration from a traditional telephony network towards a multi-services packet network is creating a packet-based infrastructure that will preserve the ubiquity, quality, and reliability of voice services while allowing the greatest flexibility for use of the new packet technologies. In practice, this means retaining the current telephony-related services on new packet-based deployments. In this paper, we present an architecture model that can serve in both the migration oath to that infrastructure and in all-packet solutions. The architecture model presented in this paper is an evolution of the ideas presented in [1]. We recognize the fact that most calls traverse multiple provider networks that may use different transport technologies or call/service signaling protocols. Therefore, the next step is to create a transport-independent, functional model for provider domaind. This allows the solution to address, for example, introduction of new services separately from internetworking between different transport technologies. The architecture model we present is one step away from physical implementations in equipment. Our model can be used to model existing telephony equipment and protocols. Unlike protocols protocol architectures we do not define implementable entities like Gatekeeper or Soft Switch, the elements of our model can be combined to create such entities as is appropriate. The model can also be used to design new ones. In ETSI project TIPHON [25] this model is used for standardization.